The present invention is directed to pharmaceutical compositions formulated to exhibit enhanced bioavailability of a therapeutic agent of the composition. The composition may also exhibit other additional or alternative desired characteristics. For example, the composition may also be sterile, may exhibit desired antimicrobial or preservation efficacy, may exhibit a desired degree of stability, combinations thereof or the like.
Therapeutic agents (e.g., ophthalmic drugs) of many pharmaceutical compositions are often required to be stable within those compositions. It is typically undesirable for the therapeutic agents or overall compositions to decompose or chemically or physically change to a significant degree prior to application of the agents to an individual or otherwise. For maintaining stability, pharmaceutical compositions are typically formulated with ingredients that can enhance such stability or ingredients that can minimize destabilizing effects of other entities (e.g., chemicals, ambient conditions or the like).
Surfactants are one preferred family of ingredients that have exhibited significant efficacy in stabilizing pharmaceutical compositions and/or therapeutic agents thereof (particularly aqueous ophthalmic solutions including relatively lipophilic and/or relatively insoluble components). Moreover, it has generally been believed that stability of an agent or composition can often be achieved by using larger concentrations of surfactant within that pharmaceutical composition.
In addition to stability of the agents or compositions, it is also typically desirable for the therapeutic agents of the pharmaceutical compositions to exhibit relatively high degrees of bioavailability. Such bioavailability often becomes particularly important where the method or manner of application or dosing of a particular pharmaceutical composition provides only a limited amount of time for the therapeutic agent of that composition to be absorbed or otherwise taken in by a biological target such as an eye, ear, throat or nose of an individual. As an example, topically applied ophthalmic pharmaceutical compositions may only dwell in or on an individual's eye for a limited period of time (e.g., before tears transport the composition elsewhere). Thus, it is often desirable to limit the concentration of any ingredient in a pharmaceutical composition where that ingredient tends to inhibit bioavailability of a therapeutic agent of that composition.
Recently, it has been discovered that surfactants, when used at certain higher concentrations, may act as an ingredient that can limit the bioavailability of a therapeutic agent, particularly an ophthalmic therapeutic agent. As a consequence, the addition of surfactant to pharmaceutical compositions and particularly ophthalmic compositions can limit the bioavailability and, in turn, the efficacy of the therapeutic agent in the composition. However, as suggested above, surfactants can also be quite desirable in a pharmaceutical composition since they can significantly enhance the stability of a pharmaceutical composition or therapeutic agent.
In view of the above, it would be desirable to provide a pharmaceutical composition with a lower surfactant concentration and/or a higher bioavailability of a therapeutic agent. Moreover, it would also be desirable, although not required unless otherwise specifically stated, for such composition to exhibit a desirable level of stability.